Pond86: Unless Microsoft have their way and totally lock down Windows to only allow apps from their store
MS has tried to nudge the Windows world at least twice already towards that, first with Windows RT, and later with Windows 10 S. They were (are) experiments to test how ready the Windows users are for the master plan, and MS backtracked from them when they saw fit. I am quite sure they will keep trying.
Pond86: , and make that the only Windows version that works (which will not happen, as they would get the biggest backlash ever.) Then the Microsoft Store taking off is not going to happen anytime soon.
MS is not stupid. Naturally they are not going to try to achieve it overnight, but little by little. Make Win32 less and less relevant and UWP more and more relevant, bit by bit.
Same as with MS-DOS. Home users didn't want to move to Windows NT because that would have meant not being able to run all their favorite MS-DOS software (like games etc.). Microsoft introduced Windows 95 with the ability to run also MS-DOS software (sometimes directly from Windows, and if all else fails, even booting out of Windows 9x into a real MS-DOS mode).
At the same time MS made sure MS-DOS is becoming less relevant and people would more and more do also their gaming in Win32. instead of MS-DOS. Developers migrated to Windows as well, and in the late 90s stopped making MS-DOS games altogether.
Then, when the time was ripe, MS released Windows XP where you couldn't run MS-DOS games anymore. People didn't care that much anymore as most of them were running solely Windows software only at that point.
With the case on Win32 => UWP, it makes even more sense to MS as that will definitely mean more income to them too if in the future people will buy their PC software and games through the MS Store, and not Steam, GOG, whatever. The same how people buy their Android software mostly from Google Play, or their iOS games from AppStore.